Surfacing machine



July 30, 1929. A. E. MAYNARD Er AL Y SURFACNG MACHINE Filed Oct. 25, 1923 5 Sheets-Sheet l` INVENTOR AE. MA VAI/WP. W A. GU/V/W'N. BY

v SEY Illy 30, 1929- A. E. MAYNARD ET An. 1,7221586.

SURFACING MACHINE Filed Oct. v25. 1923 5 Sheets-Sheet 2 (7 lNvENToR (75% Af. MAY/mm1.

nm. @www/va.

TTORNEY July 30, 1929- A. E. MAYNARD Er AL 1,722,586

* SURFACING MACHINE Filed Oct. 25, 1925 INVENTOR AEMAVNARD.

5 Sheets-Sheet 3 July 30, 1929 A. E. MAYNARb Erm. '15722,585.,

SURFACING MACHINE Filed 0G11. 25, 1923 S-SheetS-Sheet INVENTOR Patented July 30, lQZQ.

FUNE'F STTFLS trasse ratifiant carica.

ALBERT E, MAYNARD AND WILLIAM A. GU'NNNG, OFSOUTHBRIIDGE, MASSACH'U-r SETTS, ASSIGNOR-S TO AMERICAN OITICAL COMPANY, OF'SOUTHBRIDGE, MASSA- CHUSETTS, A VOLUNTARY ASSOCIATION 0F MASSACHUSETTS.

sUnrAcINe MACHINE.

Application lcd October 25, 1923. Serial No. 670,66.

This invention relates to improvements in machines for grinding and polishing lenses, and has particular reference to that type of machine wherein a lens and a grinding tool are superimposed in frictional contact, and l moved relative to one another in such a way that the curvature of the tool surface will be imparted to the surface of the lens.

One object of the present invention is to provide an improved lens grinding and Apolishing machine wherein a lens to beground and an abrading tool are positioned in frictional contact, and relatively rotated in opposite directions.

Another object is to provide such a machine wherein a lens is arranged eccentrically on. a rotating lap and moved bodily in an orbital path having a direction of rotation opposite to that of the rotating lap.

Another object is to provide improved means for varying theeccentric relationship between the lens and the lap.

Still another object is to provide such a machine witha yieldable spindle for exerting a constant pressure on the lens while revolving the lens in its orbital path.

A further object isto provide a lens grinding machine with a yieldable spindle whereby the pressure on the lens against the lap may be varied by the operator according to the ynature of the work being done.

A still further obj ect is to provide improved means whereby the angularity of the lens spindle may be varied according to the curvature of the lap so that the pressure of the lens against the tool-maybe applied in ,a line substantially passing through the center of curvatureof the tool or lap.

Another obj ect is to provide such a machine with a lens spindle which is supported by a telescoping arm, the adjustment of which overcomes all tendencies of chattering.

Another object is to provide means for readily disconnecting the lap from its spindle to facilitate changing same.

lith these and other objects in view, the invention resides in the novel features of construction, combination and arrangement of parts hereinafter fully described, illustrated in the accompanying drawings, and specifically pointed out in the appended claims.

In the accompanying drawings, wherein Figure 1 is a perspective view of our improved lens grinding machine.

Figure 2 is a vertical transverse sectional view. v

Figure 3 is a fragmentary front elevation, with parts broken away, and parts in section.

Figure 4 is a horizontal sectional view on the line 4-4cf Figure 2.

Figure 5 is a top plan View, theL lens spinle being tilted to one side. y

Figure 6 is a fragmentary sectional view on the line 6--6 of Figure 5. l

Figures 7 and 8 are diagrammatic views illustrating the adjustments possible with our machine in grindinga concave lens; and

Figures 9 and 10 are similar views illustrating the grinding of a convex lens.

Similar reference characters designate correspondingY parts throughout the several views of the drawings.

Our improved machine comprises a base 11 of any suitable shape, and preferably provided with a removable top plate 12 and a fixed bottom 13 which tapers towards the center, as clearly shown in Figure 2. The bottom 13 is formed with suitable journals l14 and 15 in the former of which is mounted for rotation the vertical spindle 16. Keyed to the spindle 16 is a spiral gear'17 .which is supported by a` roller thrust bearing 18A on the journal 14. The spindle 16 has anenlarged upper end 19y which is journaled as at 2O vin the removable top plate 12v and carries a cupped washer 21 which surrounds the upstanding journal boss 22.

A horizontal drive shaft 23 is mounted in the bearings 24 of the base 11, said shaft having keyed thereto within theV base'll thespiral gear 25 and worm 26. the casing 11 is a drive pulley 27 keyed to the shaft 23\ and a loose pulley 28 rotatably mounted on the shaft. The vertical shaft 29, journaled at 15, carries a gear 30 which meshes with worm 26 and transmits Amotion therefrom to gear 31 secured to shaft 32. From the foregoing it will be apparent that by rotating the .pulley 27 motion will be transmitted through the gearing described to the spindle 16 and the shaft 32 simultaneously.

An angular frame 33 is rigidly secured to Exterior of alignment with the shaft 32, and swivellyV mounted in this bore is the sleeve 40, having at its upper end the housing 4l and the forwardly extending tubular member 42. The upper end ofthe boss 36a is slotted on one side as 43 (Figure 5) and provided with a manually controlled clamp 44, whereby the sleeve may be securely held after beiiig adjusted about its vertical center. The object of this adjustment will be explained hereinafter. l

Suitably journaled in the sleeve 40 is a shaft 45 which is connected at its lower end vto theshaft 32 by meansof universal joints 46, and splined at its upper end to a bevel gear 47 inthe housing 41. The spline joint is necessary yso that when the bracket 36 is tilted on its pivot 35 the shaft 45 will be free to move longitudinally with relation to the gear 47. Y L

Telescoping Within the tubular member 42 is a sleeve 48 provided at its outer end with the upper spindle supporting head 49, and in which is rotatably mounted a two part extensible shaft 50 which has secured to one end a bevel gear 5l meshing with gear 47, and to its other end afbevel gear 52. The upper side of the sleeve 48 may `have a portion of its circumference grooved in the form of a rack 53, engageable by the pinion 54 mounted in the member 42. The pinion 54 is operated through the medium of a handle 55, and the bottom of the member 42 is slotted as atA 56 and provided with clamping means 57. Thus it will be seen that the upper spindle of the machine is supported on a telescoping arm which may be adjusted to any length. 1

Rising from the supporting head 49 is a tubular extension 58 provided in its sides with longitudinal openings, 59 and on its front side with a serrated member 60. A yoke 6l extends around the member 58 and carries a handle 62 having a latch 63, preferably spring pressed, for engaging the serrations in the member 60, and linger grips 64 for operating said latch. The rear end of the yoke is secured to a rod 65 which is pivoted on pin 66 in the bifurcated member`67, secured to the upper side of housing. 4l.

Secured as at 68 to the yoke V61 are a pair of transverse pins 69, which extend through the slot-S59 and support a bearing member 70 mounted for reciprocation within the tube 58. i A shaft 7l is rotatable within the bearing member 70, and provided with a telescoping extension 72 which 1s yieldingly connected by means of the compression spring 73. In order to transmit ymotion to the mem-- justable, and it is adapted to engage a cen tral depression 7 8 of a lens block 7 9 of any ordinary or preferred type.

Rotary motion will be transmitted from the shaft 32 through the universal joints 46 to the shaft 45, and thence to the telescoping shaft 50 by means of the bevel gears 52 and 7 4; then from the shaft 50 to the spindle 7 2 by means of gears 52 and 74. i ln using our improved machine, we position a lap or hard shell 8O of any suitable material, and having the proper curvature on its upper surface 8l, on the upper, preferably tapered extremity of the spindle 16. A'number of laps are kept on hand withea'ch machine, each lap having a certain standard curvature, and in grinding the upper surface 8l is'preferably the bare metal, while for polishing itis covered with a sheet of felt or other suitable soft material. The lens 82 to be surfacedis then secured to the block 79 and Placed upon the lap, whereupon the upper spindle 72 is lowered by means of the handle 62, .to vpress thellens against the lap'. Any suitable abradant such as ground emery moistened with Water, is applied to the lap, and by producing relative movement between the lens and lap, a 1contrageneric curve will be imparted to the ens.

As is well known to those skilled in the art, it is desirable that the pressure applied to hold the lens in frictional contact/with the lap should be applied approximately ina radial line with the center of curvature of the lap, and since the lens is applied eccentri'cally to the lap it is necessaryl that its actuating spindle should be disposed at an angle with relation tothe axis of the lap. With this object in View we have constructed our upper spindle supporting means in vsuch a way as to be readily and accurately adaptable to any lap curvature, either concave or convex. Thus in positioning a lens for grinding the transverse supporting arm designated generally by the letter A is swung radially about the axis of the shaft 45, and the bracket 36 is adjusted angularly on its pivot 35. The operator makes these adjustments so that the axis of the upper spindle will intersect that of the lower spindle at the center of curvature of the lap surface, and when the parts are in their proper angular position they are locked against accidental displacement by locking means 37 and 44.

We have found from experience that in the machines used prior to our invention there has been considerable chattering of the lens, which, aside from being annoying to the operator of the machine, affects the correctness of the curve formed on the lens, and we have overcome this objectionable feature by having the supporting arm A extensible. Thus after the upper spindle has been set at the proper angle as described in the preceding paragraph, the length of the arm A is adjusted, this being illustrated diagrammatically in Figures 7, 8, 9 and 10. In the particular embodiment illustrated and described herein, the arm A has to be lengthened in grinding a concave lens with the lens on the left hand side of the lap. In this way the center of the spindle 72 is thrown a distance B forward of the center of the lap, the distance being dependent upon the curvature. Thus for a curve of large radius, the distance B would be greater than for a short radius, and if the lens is positioned on the right hand side of the lap the center of the spindle should be slightly to the rear as at C in Figure 7.

For grinding a convex lens with the same direction of rotation of the parts the vvariation in the length of the arm A will be reversed, as shown in Figures 9 and 10.

As has beenpreviously stated, the spindle 72 is yieldable and may be raised or lowered by means of the handle 62. From this it will be evident that the amount of pressure on the lens may be varied according to the nature of the work to be done, and the adjusted position will be maintained by virtue of the latch 63 engaging the notched or serrated membe'r 60.

In order to catch the abrading material which is thrown off the lap by centrifugal force, we provide a pan having a bottom 83 and a continuous side wall 84 which extends upwardly a suitable distance above the top of the lap 80. The bottom 83 has a central opening surrounded by an upstanding annular flange 84:', the opening being smaller than the top of the hand shell. The pan rests upon a substantially frustoconical supporting member 85, which is detachably secured to the plate 12 by means of the clamping screws 86 engaging the lateral bearing members 87 (best shown in Figure 5), which are provided with oppositely disposed bayonet slots 88.

ln removing the hand shells from the spindle after using, operators have had some difculty with the hand shell sticking to theV tapered end of the spindle in prior art machines and quite frequently laps are damaged and broken by hammering or other abuse in removing them. 'lo overcome this objectionable feature, we provide a lever 86 which A compression spring 92 is disposed below v the lever 86r outwardly of the pivot to hold the terminal portions 91 normally out of engagement with the lap.

It will be evident that by grasping the han-` dle 89 and quickly depressing it, the lap may be easily loosened from the spindle without any possibility of Vbeing damaged. When there is no lap on the spindle the pan and its supporting member may be lifted off the plate 12 by first loosening the clamping screws 86 and revolving the member 85 sulficiently to clear the bearing members 87.

From the foregoing description it Vwill be readily apparent that we have produced a lens grinding and polishing machine which will be universally adaptable to operate accurately onlenses of any curvature, will be strong, durable, and efficient in service and a great improvement in the art. Obviously the invention is susceptible of various changes in the form, proportions and minor details of construction, and the right is herein reserved to make such changes falling within the scope of the claims without departing from the spirit of the invention.

4 Having thus described our invention, what K of the spindle which it supports whereby the lens holder may be moved towards and away from the center of the tool, means for angling the spindle supported by the arm whereby the said spindle may be angled in a plane normal to the line of movement wherein the length of the support arm is changed to assume a position such that the extension of its axis will substantially pass through the center of curvature ofthe tool to prevent the lens holder from flying off during the surfacing'operation at high speeds, and means connected with the spindle supported by said arm whereby the travel of the lens holder about the axis of said spindle may be increased or decreased to regulate the surfacing travel of the lens holder over the tool.

llO

2. In a device of the character described, a pair of opposed spindles, one carrying Va surfacing -tool and one a lens holder, an arm supporting one of the spindles, slidable means for changing` the length lof the arm whereby the lens holder may be moved towards or away from a median line of the tool to prevent chatter of the lens on the tool during' surfacing, means for pivoting said arm whereby it may be swung in a plane normel to the `anis of the spindle which it supports whereby the lens holder may be moved to Wards or away from the center of the tool, pivotal means :for angling' the spindle supported by i'he arm whereby the said spindle may be angled in a plane normal to the line of movement wherein the length of the'support arm is changed to assume position such that the extension of its aiis will substantially pass through the center of curvauie of the tool to prevent the lens holder `from flying; olf during the surfacing)rv operations at high speeds, and adjustable means connected with the spindle supported by said armv whereby Jthe travel of the lens holder about the axis of said spindle may be increased or decreased to regulate the surfacing` travel of the lens holder over the tool.

ALBERT E. MAY-NABU.

l/VlLLIAM 'A. GUNNING. 

